JP3408028B2 - Fuel cell and start-up method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell, and more particularly to a fuel cell provided with a catalytic combustor for catalytically burning unreacted hydrogen gas.

[0002]

2. Description of the Related Art In a fuel cell, an anode gas (hydrogen-rich fuel gas) and a cathode gas (air) are supplied into a fuel cell main body, and electricity is generated by an electrochemical reaction between the two. In small-sized fuel cells, particularly in portable fuel cells, relatively lightweight and small-sized hydrogen storage alloy tanks, hydrogen cylinders, and the like are often used as a source of anode gas.

Since the hydrogen storage alloy tank is smaller than a hydrogen cylinder or the like and is excellent in the storage property of hydrogen gas, the whole fuel cell is downsized and simplified as compared with the case where the hydrogen cylinder or the like is used. Etc. can be easily achieved. By the way, since the hydrogen gas release process of the hydrogen storage alloy tank is an endothermic process, if the hydrogen storage alloy tank is installed at room temperature, the hydrogen storage alloy tank becomes low temperature as the hydrogen gas is released, and the hydrogen gas release hardly occurs. Therefore, in order to continuously release a large amount of hydrogen gas from the hydrogen storage alloy tank, it is necessary to heat the hydrogen storage alloy tank.

Therefore, conventionally, in the portable fuel cell, the hydrogen storage alloy tank is installed on the downstream side in the flow direction of the exhaust air from the fuel cell body, and is heated by heat exchange with the exhaust air to release hydrogen gas. It was being promoted. In such a portable fuel cell,
It is necessary to raise the temperature of the fuel cell main body at the time of start-up because electric power cannot be supplied to the outside unless the temperature of the fuel cell main body is raised to a predetermined temperature. This temperature raising method is performed by using hydrogen from the hydrogen storage alloy tank in the fuel cell body to generate power, and heat generated by the power generation or the generated electric power to operate the starting heater to generate the fuel cell body. Was being heated.

[0005]

However, at the time of startup, since the temperature of the exhaust air discharged from the fuel cell main body is low, the exhaust air has a weak force for heating the hydrogen storage alloy tank, and the hydrogen storage alloy tank is weak. The supply of hydrogen gas from Japan was not sufficient. As a result, it was difficult to obtain the generated electric power because the electrochemical reaction was difficult to be promoted when the fuel cell was started. Therefore, there is a problem that it takes a long time to raise the temperature of the fuel cell main body, and the time from the start of the fuel cell start until the external output becomes possible (that is, the start time) is long.

In view of the above problems, the present invention provides a fuel cell using such a hydrogen storage alloy tank,
An object of the present invention is to provide a fuel cell and an operating method capable of shortening the startup time.

[0007]

In order to solve the above problems, in the invention according to claim 1, a hydrogen storage alloy tank for storing hydrogen, hydrogen supplied from the hydrogen storage alloy tank, and air are used. And the fuel cell body that generates electricity
The first exhaust air discharged from the fuel cell body is the fuel cell
The flow section that circulates from the main body to the hydrogen storage tank, the catalytic combustor that catalytically burns unreacted hydrogen discharged from the fuel cell main body, and the second exhaust air discharged from the catalytic combustor are stored in the hydrogen storage alloy tank. It is characterized in that it is provided with an exhaust air duct formed so as to be locally brought into contact with the surface of the hydrogen storage alloy tank.

In this case, in the catalytic combustor, the exhaust air discharged from the catalytic combustor becomes 100 ° C. or higher immediately after hydrogen is introduced into the catalytic combustor due to the hydrogen combustion reaction. By applying the exhaust air to the surface of the hydrogen storage alloy tank, the hydrogen storage alloy tank can be heated in a short time. As a result, hydrogen gas can be efficiently supplied at the time of starting the fuel cell, and the starting time can be shortened.

Further, a narrow region of hydrogen storage alloy tank becomes high is centrally heat exchanger. Therefore, the hydrogen storage alloy tank can be effectively heated even with a small amount of exhaust air, and hydrogen gas can be efficiently supplied when the fuel cell is started.

According to the second aspect of the present invention, the hydrogen storage alloy tank for storing hydrogen, the hydrogen supplied from the hydrogen storage alloy tank, and the fuel cell main body for generating electric power using air, and the exhaust from the fuel cell main body The first exhaust air to be discharged is
A distribution unit that distributes from the fuel cell body to the hydrogen storage tank,
Comprises a catalytic combustor for catalytic combustion unreacted hydrogen discharged from the fuel cell main body, and at the time of fuel cell operation, the fuel cell
The first exhaust air discharged from the main body flows through the circulation unit,
A method of operating a hydrogen-absorbing alloy tank and heat exchange fuel cell you, when the fuel cell starts to be discharged from the catalytic combustor
The second exhaust air is locally applied to the surface of the hydrogen storage alloy tank.

Therefore, the hydrogen storage alloy tank can be heated in a short time, and the hydrogen gas can be efficiently supplied at the time of starting the fuel cell.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be specifically described below with reference to the drawings. 1 is a perspective view in which a part of the fuel cell is cut away, and FIG. 2 is a front sectional view of FIG. As shown in FIGS. 1 and 2, the fuel cell comprises a housing 1, a fuel cell body 2, a hydrogen storage alloy tank 3 and a catalytic combustor 4.

The housing 1 is composed of a front plate 14, a rear plate 15, upper and lower face plates and left and right side plates, and the interior thereof is divided into a central space, a left space 102 and a right space 104 by vertical partitions 1a and 1b. The central space is divided by the horizontal partition wall 1c and the central lower space 101 is formed.
And the central upper space 103. here,
The fuel cell body 2 is mounted in the central lower space 101, and the hydrogen storage alloy tank 3 is housed in the left space 102. In addition, the central upper space 103 and the right space 1
The air flows from the slit-shaped air intake ports 16 at the upper portions of the front plate 14 and the back plate 15 to the air passage 04.

The vertical partition 1a has an opening (not shown) in a portion facing the fuel cell body 2, and the vertical partition 1b has an opening 10 in a portion facing the central upper step space 103. ing. Further, the upper end of the left side space 102 has an opening 11, and a closing lid 13 having a slit-shaped air discharge port 12 is attached to the upper end edge portion of the opening 11 so as to be openable and closable.

In the fuel cell main body 2, a plurality of cells, each having an anode on one surface of the electrolyte layer and a cathode on the other surface, and a separator having hydrogen and air passages are alternately arranged. In the stacked battery stacks 20, an air supply manifold 21 communicating with an air supply fan 22 is arranged on the right side of the battery stacks 20, and a hydrogen supply manifold 23 and a hydrogen discharge manifold 24 are arranged on the upper and lower parts.
Are arranged, and the left side portion is configured to be opened (not shown).

That is, the fuel cell 2 is set such that the air supply manifold 21 faces the right side space 104 and the open left side faces the left side space 102.
The air from the air supply fan 22 is indicated by a white arrow A in FIG.
As indicated by B and B, the fuel cell body 2 flows from the right side to the left side, and the exhaust air exchanges heat with the hydrogen storage alloy tank 3 to heat it.

The hydrogen storage alloy tank 3 comprises a pair of columns 3
1 and 31, a plurality of cylindrical hydrogen storage alloy tank single bodies 3a (5 in the illustrated example) are arranged in a line in a horizontal posture. All the hydrogen storage alloy tank single bodies 3a are communicated with each other by a passage (not shown) formed in one of the columns 31, and the coupler 3 serving as a hydrogen outlet is provided at the upper end of the passage.
Two are provided. The coupler 32 and the hydrogen supply manifold 23 are connected by a hydrogen supply pipe (not shown) so that hydrogen gas is supplied to the fuel cell main body 2. On the other hand, an unreacted hydrogen supply pipe 50 is connected to the hydrogen discharge manifold 24, and unreacted hydrogen is supplied to the catalytic combustor 4.

The catalytic combustor 4 is, as shown in FIG.
It is composed of a combustion section 4a, an air supply section 4b, and an air discharge section 4c. The combustion section 4a has a configuration in which a rectangular box body 400 having openings (not shown) at the upper end and the lower end is filled with a catalyst layer in which a platinum catalyst is held by a honeycomb-shaped holder. . In addition, an unreacted hydrogen supply pipe 50 having a hydrogen supply nozzle (not shown) at its tip is inserted into the box body 400, and unreacted hydrogen discharged from the fuel cell body 2 is introduced into the inside. It is supposed to be done.

The air supply unit 4b has a structure in which a catalyst air supply fan 412 is attached via a cylindrical tube 411 to the lower portion of a rectangular tube 410 whose upper end is open (not shown). It is arranged below 400. Then, the air is introduced into the box 400 by the operation of the catalyst air supply fan 412. The air discharge part 4c is composed of a cover body 420 that covers an upper end opening (not shown) of the box body 400, and a discharge air duct 422 that extends laterally from its side. Then, the exhaust air from the box 400 is exhausted by the exhaust air duct 42.
It is designed to be discharged from the catalytic combustor 4 through 2.

The inner wall of the exhaust air duct 422 is made of a heat insulating material, and as shown in FIGS. 2 and 3, the exhaust air duct 422 is laid horizontally in a space between the fuel cell body 2 and the front plate 14. Further, the exhaust air duct 422 is connected to the vertical partition 1.
a, and the end portion 423 on the air outlet side is a specific hydrogen storage alloy tank single body 3a (from the top in FIG.
It is located in the vicinity of (main line) and is bent so that the exhaust air hits the hydrogen storage alloy tank single body 3a toward the center in the longitudinal direction.

The catalytic combustor 4 having the above structure is installed in the central lower space 101. At that time, the box 400,
The rectangular tube body 410 and the cover body 420 are assembled in the recess 25 formed in the air supply manifold 21. In addition, the cylindrical tube 411 is a vertical partition wall 1.
b, and the catalyst air supply fan 412 is connected to the right side space 1
It is located within 04.

In the catalytic combustor 4 described above, when the fuel cell is started and operated, air is supplied from the outside of the housing 1 and hydrogen is supplied from the unreacted hydrogen supply pipe 50, and catalytic combustion is performed in the combustion section 4a. It Then, the exhaust air at that time is exhausted into the left side space 102 through the exhaust air duct 422 as shown by a black arrow C in FIG. Here, the cross section of the exhaust air duct 422 is set to such a size that the exhaust air efficiently hits the hydrogen storage alloy tank single body 3a in an appropriate amount. Further, the distance between the air outlet side end portion 423 and the hydrogen storage alloy tank single body 3a is about 15 so that heat can be efficiently exchanged with the hydrogen storage alloy tank single body 3a even with a small amount of exhaust air.
It is set to mm.

At the time of starting the fuel cell, the exhaust air from the catalytic combustor 4 becomes high in temperature in a short time due to the catalytic combustion reaction.
Therefore, the high-temperature exhaust air hits the specific hydrogen storage alloy tank single body 3a in a concentrated manner, so that more hydrogen gas is released from the hydrogen storage alloy tank single body 3a. Therefore, the electrochemical reaction in the fuel cell body 2 is promoted,
More power is generated. As a result, the temperature of the fuel cell body 2 is effectively raised in a short time after starting by the reaction heat of the electrochemical reaction, the starting heater (not shown) operated by the generated electric power, and the like.

In the fuel cell, when the temperature of the fuel cell body 2 reaches 50 ° -80 ° C., electric power can be taken out to the outside, so that the temperature of the fuel cell body 2 is raised in a short time. This leads to a reduction in the battery startup time. This means that the fuel cell main body 2 with respect to the start-up time
This is supported by FIG. That is, as can be seen from FIG. 5, the startup time of this embodiment is clearly shorter than that of the conventional example.

In the above embodiments, an example of a portable fuel cell was shown, but the present invention is not limited to this, and a fuel cell equipped with a fuel cell body, a hydrogen storage alloy tank and a catalytic combustor is used. If so, it can be implemented in the same manner and the same effect can be obtained. In addition, in the present embodiment, the exhaust air from the catalytic combustor 4 exchanges heat with the specific one hydrogen storage alloy tank single body 3a, but the hydrogen storage alloy tank single body 3a is the second one from the top. It is not limited to, and any number from the top may be used. Further, the number of the hydrogen storage alloy tanks is not limited to one specific one, and heat exchange may be performed with a plurality of hydrogen storage alloy tank single bodies 3a.

[0026]

As described above, according to the first aspect of the invention, in the catalytic combustor for catalytically burning the unreacted hydrogen discharged from the fuel cell body, the catalytic exhaust air is provided in the vicinity of the hydrogen storage alloy tank. locally the surface of the hydrogen storage alloy tank leads
There is provided an exhaust air duct formed so as to hit the.

The exhaust air from the catalytic combustor becomes hot in a short time due to the hydrogen combustion reaction. Therefore, by applying the exhaust air from the catalytic combustor to the hydrogen storage alloy tank, the hydrogen storage alloy tank can be heated in a short time, and the hydrogen gas can be efficiently supplied at the time of starting the fuel cell. . As a result, since the electrochemical reaction at the time of starting the fuel cell is promoted and sufficient generated electric power can be obtained, the temperature of the fuel cell main body is raised in a short time, and the starting time can be shortened.

Further, since the narrow region is intensively heat exchanger, a small amount also can be effectively heated hydrogen storage alloy tank with exhaust air, when the fuel cell starts to perform efficiently the hydrogen gas supply You can Therefore, the effect of shortening the startup time is great.

According to the second aspect of the invention, the temperature of the exhaust gas from the catalytic combustor becomes high in a short time as described above. Therefore, by locally applying the exhaust air from the catalytic combustor to the surface of the hydrogen storage alloy tank, the hydrogen storage alloy tank can be heated in a short time, and an efficient hydrogen gas at the time of starting the fuel cell can be obtained. Supply can be done. Further, since the electrochemical reaction at the time of starting the fuel cell is promoted and sufficient generated electric power can be obtained, the temperature of the fuel cell main body is raised in a short time, and the starting time can be shortened.

[Brief description of drawings]

FIG. 1 is a perspective view in which a part of a fuel cell according to the present embodiment is cut away.

FIG. 2 is a front sectional view of FIG.

FIG. 3 is a plan sectional view of FIG.

FIG. 4 is a detailed view of the catalytic combustor 4.

FIG. 5 is a diagram showing changes in internal temperatures of a catalytic combustor, a fuel cell body, and a hydrogen storage alloy tank in the fuel cell according to the present example and the conventional example.

[Explanation of symbols]

1 housing 2 Fuel cell body 3 Hydrogen storage alloy tank 4 catalytic combustor 4a Combustion part 4b Air supply unit 4c Air discharge part 422 Exhaust air duct

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shingo Washimi 2-5-5 Keihan Hondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (56) Reference JP-A-3-101062 (JP, A) (58) ) Fields surveyed (Int.Cl. ⁷ , DB name) H01M 8/00-8/24

Claims (2)

(57) [Claims] 1. A hydrogen storage alloy tank for storing hydrogen, a fuel cell main body for generating electric power by using hydrogen and air supplied from the hydrogen storage alloy tank, and a first exhausted from the fuel cell main body. Exhaust air is
Distribution unit that distributes from the fuel cell body to the hydrogen storage tank
A catalytic combustor for catalytically burning unreacted hydrogen discharged from the fuel cell main body; and second exhaust air discharged from the catalytic combustor to the vicinity of the hydrogen storage alloy tank to store the hydrogen storage A fuel cell, comprising: an exhaust air duct formed so as to locally contact the surface of the alloy tank. 2. A hydrogen storage alloy tank for storing hydrogen, a fuel cell main body for generating power using hydrogen and air supplied from the hydrogen storage alloy tank, and a first fuel cell for discharging the fuel cell main body. Exhaust air is
Distribution unit that distributes from the fuel cell body to the hydrogen storage tank
And a catalytic combustor that catalytically burns unreacted hydrogen discharged from the fuel cell body, and is discharged from the fuel cell body during operation of the fuel cell.
The first exhaust air circulates through the circulation unit and absorbs the hydrogen.
A method of operating a storehouse alloy tank and heat exchange fuel cell you, when the fuel cell starts, the second discharged from the catalytic combustor
2. The method for operating a fuel cell, wherein the exhaust air of 1. is locally applied to the surface of the hydrogen storage alloy tank.